In effort to find a good answer I've been all over the internet looking for an answer to exactly how thick of a layer of crushed rock and how thick of a layer of sand to use for a patio. Or at the very least what the ratio should be.

The difference in answers is enough for me to not be able to make a good choice. Not wanting to have it too thin is my main goal. Seeing as I've already moved 1600 (5 to 8 lb ea), 4"x4"x8") bricks by hand to where the patio is going to be, I'm not really all that worried about moving a ton or so of crushed rock. What's a little more of a workout right? I'm also not trying to skimp. If I need 4 inches of crushed rock, then I'm doing it.

Also because I'm a big user of the SE network, I figured where better to help find an answer to my question. My goal, do it right the first time.

3 Answers
3

I just completed a 90 square foot patio. I ended up putting down 4 inches of paver base (crushed concrete), 1 inch of sand, and then the 2 inch patio stones... so I dug down 7 inches all around. To be honest though, I went deeper than that in some places and ended up having to bring in much more paver base (crushed concrete) than I really needed. So maybe I have 6 inches of paver base in some areas. In my opinion, the key was the compacting. I highly recommend you rent a plate compactor. You should be able to rent one for less than $100 for 4 hours and it is completely worth it. You will only use it for 30 minutes but it will make the crushed concrete as solid as rock.

Also one of my neighbors who is a landscaper joked about how far I had dug down... he said I went way too deep and now I can land a helicopter on my new patio. I tend to agree with him that the 4+ inches of paver base was more than needed but still I am happy with how it all turned out.

Couple other notes:

After compacting the crushed concrete it was smooth and solid. When you walked on it nothing moved... kind of like walking on concrete.

Lowes/Home Depot sell paver base by the bag but that is much more expensive than having it delivered. 2 tons (approximately 1 cubic yard) of crushed concrete was not enough to cover my 90 square feet to a depth of 4 inches; I probably ended up putting down 3 tons.

Since the patio was positioned next to a concrete sidewalk, I used an 8' 2x4 with a piece of scrap wood nailed to one end which gave me a depth of 3 inches (the sand and paver depth). Then I pulled the 2x4 back and forth across the area (with another person holding one end on the sidewalk) to level out the paver base before compacting (and to know where the shallow/deep spots were).

I used 1 inch diameter pipes to give me the 1-inch depth for the leveling sand. Put two pipes down on the compacted paver base parallel to each other and then pour the sand on top. Then pull a 2x4 over the pipes to level the sand. Remove the pipes and then fill in the indentation by hand. Now lay your pavers (or patio stones).

I used polymeric sand to fill the cracks in between the individual patio stones.

Did you put anything under the crushed rock for future weed control? Something like a plastic lining or as I read somewhere, a layer of tar paper that is used for under shingles on a roof? It just so happens I have the majority of a roll left of the tar paper from building my shed last year and figured it might be a good way to use some of it.
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Tim MeersApr 13 '11 at 12:36

No, I didn't put anything under the crushed rock. But it is compacted so well that nothing is going to grow in that. I have seen recommendations of adding Preen into the leveling sand but I didn't do that either. Also the polymeric sand in between individual stones set very nicely so I do not think weeds are going to get in there (of course we'll see how this all turns out by the end of the summer).
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Jeff WidmerApr 13 '11 at 13:44

@JeffWidmer Did anything end up growing through the patio?
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Chris Marasti-GeorgMay 20 '13 at 13:30

It really depends on what part of the country you are building in. The method is much different in the frozen north than the sunny south. I do not like crushed stone with a gravel overcoat. the sand will eventually settle into the stone and leave voids under the pavers.. I am a firm believer in stone dust. 3/8 stone dust, wetted and compacted is like a concrete base. In the north country, we may dig out a foot of subsoil, 6 inches of packing gravel and 6 inches of stone dust. compact well. In no freeze areas, 4 inches over a stable subsoil is fine. Compacting the base is an extra step, but will pay off in a long lasting even deck.